Pneumatic tire pressure gauge



Jan. 17, 1933. f A. w. HOBSON 1,894,490

ENEUMATIC TIRE PRESSURE GAUGE Filed Oct. l1, 1929 lfll/w A.' v/y (h4-l un l l l l INVENTOR. ,4R f/Uh/Hoasam ATTORNEYS.

f ,f 40 shaped edge.

Patented Jan, A17, 1933 ARTHUR w. HoBsoN, or sAN rRANoIsco, CALIFORNIA PATENT OFFICE PNEUMATIG TIRE PRESSURE GAUGE Application filed.k October 11, 1929. Serial N0. 398,980.y

My invention relates to improvement in a pneumatic tire pressure gauge and it consists in the combinations, constructions, and arrangements 'hereinafter' described and claimed.

Y i An object of invention is to provide a tire pressure gauge thatv isfdesigned' to be f applied to the exterior surface of the tire and to indicate the air pressure within the tire.

.'10 This` device does not have to be applied to the' valve stem," as is usually the case with standard tire ressure gauges.

A further o jectofmy invention is'to pro- :vide a device of the type described that'makes '1.5 use of a spring that will be uniformly compressed in a direct ratio to the number of pounds of force directed against the indicating' mechanism. This permits a scale to be used that has equal graduations. A pointer pressure within the tire. p

The device further makes use of novel means for changingl a relatively small movement into a much longer movement so that 1120 moves over the scale and indicates the air i 2.5 the reading of the ltire air pressure ismade easy. Y A p n n. till a further advantageis obtamed from Vthe mechanism which holds the indicator after it has been moved into its furthest posi- 113.10 tion, yetl permits the actuating plunger to return to normal position. The indicator returns to normal position upon they pressing yof a release button.

The gauge has a rectangularly shaped end i "135 that is designed to be placed against the'surface ofthe tire. AThis end is hollowed out l.15y in construction and is durable and efcient for the purpose intended. c

Other objects and advantages will appear in the following specificatiomandthe novel features of my invention will be particularly pointed `outin what Iihereinafter. claim.

vMy invention is illustrated in the accomlpanying drawing forming apart ofthis application, in which v Y F igure'l is a front elevation of the device.

Figure 2 is a section along the line 2-2 C56 of Figure 1.

Figure 3 is a top plan Vview of the device.

Figure 4 is a section along the line 4-4 of Figure 2.

Figure 5 is similar to Figure 1, but shows the cover plate removed.

Figure 6 is a section along theline 6-6 of Figure 2.

Figure 7 is a perspective view of a part of the device.

Figure 8 is a vlongitudinal section Y of a modified form of the device, and

Figure 9 is aperspective view of a part of the device shown in Figure 8.

In carrying out .my invention I provide a ycasing indicated generally at 1. This casing has a hand grip portion 2, an enlarged portion 3, (see Figure 4) for receiving the actuating mechanism, and a head portion 4 that is .A designed tojbe brought into contact with the exterior surface of a tire casing 5, (see Figcasing enclosedby the -rectangular edge 7' can flex indirect ratio Vwith the amount of air pressure contained within the tire. The amount of lflexing of the tire casing is recorded `Ona dial 8, (seek Figures y1 and "5),

f and the mechanism connecting a pointer 9,

movable over the dial, with the tire casing, will now be described. A spring pressed pin or plunger 10, (see Figure 4), is centrally disposed in the head portion 4 and normally projects beyond the edge 7. The pin 10-enters the casing 1 and h'as a shoulder 11 that limits the downward movements of the pin. A lspring 12 bears against the shoulder of the annular flange 11, and also bearsagainst n a'guide member 18. A movement of the pin l10l inwardly will compress ythe spring 12. The spring is designedto "be uniformlyfcom- 1 00 pressed in direct ratio to the increase of the force exerted against the pin.

A guidemember 13 is carried by screws 14 and is adjustablylocked in place by nuts l5. The pressure of the spring 12 is varied by means of this adjustment.

The pin carries a rack 16 and this rack meshes with a pinion 17 that is formed integrally'with a finger 18, (see Figure 7).` .The pinion 17 and the finger 18 Vare rotated in a- .supported by a vcover'member 26, while the Yat pinion 2lis mounted on the shaft 19. The cover 26 has a window through which the dial 8 may be viewed. v Y

lt will be seen from theconstruction thus far that amovement of the plunger 10 inwardly will swing the pointer 9 over the dial 8 because the .pointer is rigidly connected to the pinion 24. The gear ratio moves the pointer 9 a considerable distance for a slight movement of the plunger 10. It will also be seen that. the dial 8-has equal `graduation marked thereon.-V Y Y i I provide Vmeans forholding vthe-pointer Y in the position into which it has been swung by the movement ofthe'plunger 10. This means is shown in Figures 5 and 6. The sector 22 has a flange v.27 withxteethnformed therein and a pawl 28` rides over. the teeth.

Figure 6 is asection taken abovezand look-V ing down upon the sector 22l andV ratchet 'teeth v27 sov that a counterclockwise. movement of thedislr20 in Figure will be an .upward movement in Figure 6. This pawl g permits movement of the disk 2O in a counterclockwise direction, when'lo'okingfat FigureV 5, but preventsa return movenf1ent. Figure 6 shows thevpawl 28 as being 'connected toa spring pressed Ipush button 29. V.Afdepressing of `thenpush button29 frees Vthe pawl Yfrom the teeth and permits ay spring 30, (see Figures l and 5), to return'the diskl to initial position.` lt should be noted that the pawl 28 mer-ely holds the disk'20' against return movement?. |The plunger 10 is free to return because the nger 18 ywill'move away fromV .the pin 21 during. the return .movement of the plunger. lWhen the dislr'20 is released, the spring 30 will rotate it until the pin 21 again strikes the finger 18.

Access may be had to the interior of the .device by means of a back Vcover 31, (see lfigure 2). .This cover has a flange 32at its 'lower edge and the top .of the cover viis plunger. Y

heldin place by a screw 33, ,or other suitable fastening means.

From the foregoing description of the various parts of the device, the operation thereof may be readily understood. r Y In using the device the handle 2 is grasped and the plunger `10 isforced against the tire Y i casing 5 untilA the edge 7 contacts with the tire casing. The pressure of air within 'the4 tire will cause the plunger 10 to be moved inwardly in direct ratio tothe amount of pressure. This movement is transmitted to the pointer 9 'in themanner. already described. y

The :pointer isheld in its new lposition by a lpawl 28, andV is only released when the push button. 29 is depressed'. -f

`i 'In Figures@ and -9 r Showanioaifitdifm ofthe device. Thisform is ,identical to .that already described except-.that it isnusedlfor high pressureand it has a plunger 50 lwhich T85 takes the place-of,V the plunger ,1(1).y ThisA plunger is similar to the plunger-10, but has in additionl a depending member l-.that slides ina guide 52. The .guide :52 takes fthe place of the vguide 13. `Ayspring- 53, having afun'iform compression, 'bears against a Vpin 54, carried by the portion 51and has fits lower end disposed'on an adjustablenut 5.5.` The nut 55 is moved by'means of-a-bolt 56 that is carried by the casing 1. f f 7'9`5 The spring53 returns the plunger50in thesame manner-as the spring 12 returns 4the plunger 10.;k The plunger-50; carriesthe rack 57, which issimilar to the rack 16. j The rack 54 meshes with the operatingxpartsand :1100 actuates theml in the.y manner-"alreadydescribed. Like reference numerals will therefore be applied.` Y xv Although l have shown andldescribedtwo embodiments of my invention, lit is tobeun- 105 derstood that the same is'susceptible of va- 'rious' changes YandY I reserve the right toemploy such changes asmay come withinthe g `scope of the invention Vas claimedj Y It should be particularly `noted that when the device is forced against the exterior-surface offa tire and is moved sofas to bringrthe Y edge 7 into a rm contact'with the tire, the pointer 9 will'register the exact-*air pressure in the tireat this .moment and will registerjl'w no more than the exactair pressure. y. 1

' 1. A tire -pressure gauge/comprising a cas- 1 ing'k having a recessed portion', the v. marginal -V Vedge of the recessbeing designed to presslzo against `the exterior 'surface Yof fa,` tire, a plunger carried by the casing andbeing centrally disposed inl said recess, said' plunger adapted to be movedfby the-reactionv pressure ofthe tire casing, and-airA pressure indi-'fV 125' eating means operatively connected to said 2. A. tire pressuregauge comprising a casing having a cup-shaped end Adefining'V an edge e adapted .tobe broughtinto contact with the''lo tire, a plunger mounted in-said casing and extending through the cup-shaped portion, a pointer operatively connected to the plunger and a dial having equal graduations over which the pointer is adapted to move.

3. A tire pressure indicator comprising a casing, a plunger slidably carried thereby and extending therefrom, said plunger being designed to bel moved against a tire, spring means for moving said plunger into extend ed position When the indicator is removed from the tire, a rack forming a part of the plunger, a pinion rotated by said rack and having an integral inger, a rotatable disc having a pin engageable by the finger when the latter is moved in one direction so as to rotate the disc, a pointer operatively connected to said disc and being movable lthereby, said casinghaving a dial over Which the pointer moves, means for holding said disc in the maximum position into Which it is moved, said last-named means being manually releasable, and spring means for returning the disc and pointer to normal When released.

4. A tire pressure gauge comprising a casing having a hand-gripping portion designed to be held against the body of the user, a pointer carried by said,I casing, a spring-pressed plunger carried by said Cas ing and being movable against a tire, said plunger being operatively connected to the pointer, said casing having the portion disposed adjacent to the plunger provided With a recess for forming an -edge that is movable against the tire, said edge When contacting With the tire causing the portion of the tire enclosed by the edge to be lexed by the plunger in direct proportion to the air pressure in the tire, the plunger moving the pointer for indicating the air pressure Within the tire.

ARTHUR W. HOBSON. 

